Electric lamp mount



Oct. 31, 1961 s. E. SWASEY ETAL ELECTRIC LAMP MOUNT Filed Sept. 14, 1959 FIE F'IEI E.

KENTON :2. BAGLEY SAMUEL E.

6 WA SEY INVENTOR5 ATTORN 3,007,074 ELECTRIC LAMP MOUNT Samuel E. Swasey, Edgemere, and Kenton R. Bagley, Beverly, Mass., assignors to Sylvania Electric Products Inc., a corporation of Delaware Filed Sept. 14, 1959, Ser. No. 839,796 3 Claims. (Cl. 313-279) This invention relates to the manufacture of electric lamps and more particularly to the manufacture of incandescent electric lamps.

Over the years, many different types, shapes, sizes, etc. of incandescent lamps have been made available commercially. Two of the basic components of many of these lamps are a mount and an envelope, the former being hermetically sealed Within the latter to define an unbased lamp. Mount structures differ appreciably from one another depending on the particular type of lamp being made. Basically, the mount structure is an arrangement of electrical conductors, usually called lead-in wires, and support wires for supporting the lamp filament in position within the hermetically sealed lamp envelope. This arrangement of wires must be rugged enough and flexible enough to provide the necessary support for the filament over a broad range of environmental installation and operational conditions as well as during transportation from the manufacturer to the ultimate user. On the other hand, it is most desirable, economically, that the mount structure be as simple as possible and readily lend itself to fabrication on a tomatic lamp manufacturing equipment. In addition to the foregoing, the attainment of these objectives, of course, should not be accomplished at the expense of light output, light distri bution and other lamp performance characteristics.

This invention relates to a mount structure for incandescent lamps in which the filament is disposed vertically within the lamp envelope, i.e., the axis of the filament is substantially coincident with the longitudinal axis of the lamp envelope.

Therefore, an object of this invention is to provide a mount structure for vertical filament incandescent lamps in which the foregoing desiderata are attained.

In the specific embodiment of the invention illustrated in the accompanying drawing, FIGURE 1 is an elevational view of an incandescent lamp with the mount structure therein shown in side elevation.

FIGURE 2 is an end elevational view of the mount structure of FIGURE 1.

Referring now to FIGURE 1, the lamp illustrated therein comprises a glass envelope 2 in one end of which a glass stem 4 is hermetically sealed. The stem 4 is provided with a stem press 6 on which a heat-reflecting shield 8 is disposed. Lead-in wires 10 and 12 are sealed in the stem press 6, the depending portions thereof extending through the throat of the stem for connection in the 'usual manner to a base 14 with which the lamp envelope 2 is provided. wires 10 and 12 are provided with offset portions 10a and 12a respectively, to which the ends of a filament 16 are attached. A glass arbor 18, mounted on top of the stem press 6, is provided at its free end with an arbor button 20. One end of each of three support wires 22, 24 and 26 is anchored in the arbor button 20. The other end of support wire 22 is provided with a loop portion which encircles the filament 16 intermediate the ends thereof to help retain the filament in position. The other ends of support wires 24 and 26 are provided with loop portions 31 and 32 which encircle lead-in wires 10 and 12 respectively at points 28 and 30 respectively.

As is shown in FIGURE 1, the lead-in wires 10 and 12 diverge at their points of emergence from the stem press. The shorter lead-in wire 12 thus extends angu- United States Patent The upper portions of lead-in 3,007,074 Patented Oct. 31, 1961 "ice larly for a short distance and then substantially parallel to the longitudinal axis of the lamp envelope, these segments being identified as 12b and 120 in FIGURE 1, and finally terminates in the offset portion 12a to which one end of filament 16 is attached. The longer lead-in wire 10 extends angularly for a short distance, this segment thereof being identified as 10b in FIGURE 1, and then substantially parallel to the longitudinal axis of the lamp envelope for a short distance, this segment thereof being identified as in FIGURE 2. The lead-in wire 10 is then bent angularly to the right and then to the left, as viewed in FIGURE 2, to defined segments 10d and 10e respectively, finally terminating in the aforementioned ofi'set portion 10a.

In the development of the above-described mount structure, it was found that the provision of angular bends to provide various segments of various lengths of the two lead-in wires contributed substantially to the attainment of the desired flexibility of the mount structure. In addition thereto, the segments 10d and We of the longer leadin wire 10 are disposed so as to effect a substantial reduction in lead-in wire shadow.

One of the more critical problems associated with the development of a high quality mount structure for a lamp of this type was the integration of rigidity, flexibility and elasticity characteristics. With an axial filament, this problem becomes particularly acute since one lead-in wire is relatively short and the other lead-in wire is relatively long. During shock tests, in some cases, it was found that the lead-in wires of unequal length flexed an unequal amount and tended to return toward their initial positions an unequal amount. Because of the greater mass and leverage, the longer lead-in Wire flexed more and had much less tendency toreturn to its initial position than the shorter lead-in wire.

The lead-in wires must have some flexibility and some elasticity because excessive rigidity must also be avoided in order to protect the filament from the brunt of a shock to which the lamp envelope may be subjected, during transportation or handling for example.

We have found that these undesirable conditions may be overcome by flattening that portion of the longer lead-in wire 10 which extends substantially parallel to the longitudinal axis of the lamp envelope, i.e., the segment identified as 100 in FIGURE 2. We have found that with this structure, the desired flexibility and elasticity as well as stiffness are obtained. We have noted that the flattened portion is stiffer under shock conditions and yet the remainder of the lead-in wire 10 is flexible and elastic enough to absorb most of the shock under adverse handling or transportation conditions. This increased stiffness is probably due to the work hardening of the nickel wire as a result of the flattening thereof. Even further improvement is noted when the support wires 24 and 26 are disposed substantially at right angles to their respective lead-in wires and engage the segments thereof which extend substantially parallel to the longitudinal axis of the lamp and not at the bends, i.e., not at the junction of segments 10b and 10c of lead-in wire 10 and the junction of segments 12b and of lead-in wire 12.

In the specific embodiment of the invention illustrated in the accompanying drawing, a 500 watt incandescent lamp in a P835 bulb is shown. The support wires 22, 24 and 26 are .012 inch molybdenum and the lead-in wires 10 and 12 are .035 inch nickel, with the narrower dimension of the flattened segment 10c being about .025 inch.

What we claim is:

1. A mount structure disposed within an electric lamp envelope having a longitudinal axis, said mount structure comprising: a filament, the longitudinal axis of which is substantially coincident with the longitudinal axis of said envelope; a stem press; and a pair of lead-in wires of unequal length anchored in said stem press and extending generally longitudinally within said envelope and along opposite .sides of the longitudinal axis of said envelope, each of said lead-in wires terminating in an inwardlyextending segment to which the ends of said filament are attached, said lead-in wires diverging as they emerge from said stern press and then extending in part substantially parallel to the longitudinal axis of said envelope, said substantially parallel segment of the longer of said pair of lead-inwires being flattened whereby great erstiffness is imparted to said longer lead-in wire.

2. A mount structure disposed within an electric lamp envelope having a longitudinal axis, said mount structure comprising: a filament, the longitudinal axis of which is substantially coincident with the longitudinal axis of said envelope; a stern sealed in an end of said envelope and extending into the interior thereof, the inner end of said stem being, provided with a stern press; an arbor mounted on said stempress, the other end of said arbor being provided with an arbor button; a pair of lead-in wires of unequal length anchored in said stem press and extending generally longitudinally within said envelope and along opposite sides of the longitudinal axis of said envelope, each of said lead-in wires terminating in an inwardly extending segment to which the ends of said filament are attached, said lead-in wires diverging as they emerge from said stem press and then extending in part substantially parallel to the longitudinal axis of said envelope, said substantially parallel segment of the longer of said pair of lead-in wires being flattened whereby greater stilfness is imparted to said longer lead-in wires; and a filament support wire extending generally longitudinally within said envelope, one end of said filament support wire being embedded in said arbor button and the other end thereof being provided with a loop portion substantially encircling said filament intermediate the ends thereof.

3. A mount structure disposed within an electric lamp envelope having a longitudinal axis, said mount structure comprising: a filament, the longitudinal axis of which is substantially coincident with the longitudinal axis of said envelope; a stern sealed in an end of said envelope and extending into the interior thereof, the inner end of said stem being provided with a stem press; an arbor mounted on said stem press, the other end of said arbor being providedwith an arbor button; a pair of lead-in wires of unequal length anchored'in said stern press and extending generally longitudinally within said envelope and along opposite sides of the longitudinal axis of said envelope, each of said lead-in wires terminating in an inwardly extending segment to which the ends of said filament are attached, said lead-in wires diverging as they emerge from said stern press and then extending in part substantially parallel to the longitudinal axis of said envelope, said substantially parallel segment of the longer of said pair of lead-in wires being flattened whereby greater stiffness is imparted to said longer lead-in wire; a filament support wire extending generally longitudinally within said envelope, one end of said filament support wire being embedded in said arbor button and the other end thereof being provided with a loop portion substantially encircling said filament intermediate the ends thereof; and a pair of support wires for said lead-in wires, one end of each of said support wires being embedded in said arbor button and the other end thereof being provided with a loop portion substantially encircling its associated lead-in wire intermediate the ends of said substantially parallel segment thereof and extending substantially perpendicular thereto.

References Cited in the file of this patent UNITED STATES PATENTS 

